• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.721-724
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• 2003

본 논문에서는 CDMA 3G 환경에서의 Wireless VPN에 있어서의 문제점을 분석하고 설계/구현 방안을 제시하고자 한다. Wireless VPN의 최종 목표는 Wireline VPN과의 통합을 이루어서 진정한 Mobile VPN을 구현하는 것이지만 아직까지 Mobile IP 지원에 대한 국제 표준이 완전히 정비되지 않은 상태이고 또한 Mobile VPN에 대한 기술적 검증이 이루어진 적이 없기 때문에 본 논문에서는 Wireless VPN에 초점을 맞추도록 한다.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.8
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• pp.37-44
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• 1997

We implemented a code searcher which is used for the PN(pseudo noise) code acquisition in CDMA cellular mobile station. To reduce the reuired hardware and the code acquisition time, we used the double dwell structure which is an effective serial code acquisition metho. We designed a code acquisition has acquired within 1/2 PN chip range. The code searcher is implemented using 0.8 micron code searcher is successfully working in CDMA cellular mobile station and it satisfies the code acquisition time specified in IS-95 standard.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.7
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• pp.641-655
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• 1992

In this paper, the performance of the various multiple accesstechniques for the mobile computer network has been studied in the consideration of the characteristics. Of the mobile communication channel. In the case of the hidden node occurring, it could be seen that the performance of the code division multiple access(CDMA) technique. With simultaneous access function is better than that of the other packet access methods such as carrier sensed multiple access(CAMA). Busy tone mulitiple access(BTMA)and idle signal muitiple access(ISMA) in the view of the throuhtput and mean delay time. Also it has been shown that the performance of the CDMA method is superior to that of other packet access techniques such as multiple access(CSMA).etc when the fading effect or impulsive noise exists in the mobile channel. Especially in the case of the distributed mobile network. It has been shown that the receiver-transmitter based CDMA method using the characteristics of CDMA effectively has better throughput and less mean delay time than the commontransmitter based CDMA technique.

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.350-354
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• 2008

IP-based mobile communication system is one of the key research items in the mobile networks for a long time. But, due to some technical issues and no need of markets, it is still not full-fledged. Recently, CDMA and WCDMA service providers want to introduce IP-based network connectivity. Even though their efforts, the main network intra-structure depends on ATM or HDLC technology. This article describes a good example of commercialization of IP-based mobile communication systems. Our research is not experimental system but a in-service system - replacing the existing equipments with new IP-based systems. In this paper, we introduce IP related technologies used in our research such as IP-based ATCA(Advanced Telecommunications Computing Architecture) platform, HA(High Availability) redundancy, IP multicast, network redundancy techniques, multi-link bundling and IP header compression. These are already well-known to internet domain. We mix them with mobile communication systems concretely.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04d
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• pp.136-138
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• 2003

인터넷은 이미 대중화되어 있으며, 이러한 인터넷 망을 기초로 한 All-IP 망으로의 망 진화에 대한 논의가 활발하게 진행되고 있다. 또한 현재 상용중인 IPv4에 이동성을 부여한 이동 인터넷(Mobile IPv4)에 대한 연구는 IETF(Internet Engineering Task Force)를 중심으로 활발하게 진행 중에 있으며, 이에 대한 구현 및 개발은 이미 많은 연구단체에서 많은 성과를 보여주고 있다. 본 논문에서는 3세대 이동통신 모델 중의 하나인 CDMA2000 1x 환경에서 기 구현된 Wire-less LAN에서의 이동 인터넷(Mobile IPv4)을 연동하여, 이기종 망(Heterogeneous Network)에서의 이동 인터넷(Mobile Ipv4) 모델을 제시한다. 제시된 이동 인터넷(Mobile IPv4) 프로토콜은 Layer-2망으로서 Wireless LAN과 CDMA2000 1x을 모두 사용하며, 하부 망(Layer-2 Network)의 변화에 능동적으로 반응하여, 통신을 유지한다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.2
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• pp.107-114
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• 2003

In this paper, we propose an efficient mutual authentication and key distribution protocol for cdma2000 packet data service which uses Mobile U access method with DIAMETER AAA(Authentication, Authorization and Accounting) infrastructure. The proposed scheme provides an efficient mutual authentication between MN(Mobile Node) and AAAH(home AAA server), and a secure session-key distribution among Mobile If entities. The proposed protocol improves the efficiency of DIAMETER AAA and satisfies the security requirements for authentication and key distribution protocol. Also, the key distributed by the proposed scheme can be used to generate keys for packet data security over 1xEV-DO wireless interface, in order to avoid a session hijacking attack for 1xEV-DO packet data service.

• Journal of Korea Society of Industrial Information Systems
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• v.9 no.2
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• pp.89-95
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• 2004

CDMA is the way that more than one users can share the time and frequency at the same time and connect with multiple access in mobile communication. Multiple Access is indispensible for mobile communication because the limited frequency is able to be used by many users in mobile communication. CDMA is also applied to home network, military, business and medical sectors. This paper, presents a users should share limited frequency resource. CDMA module implemented with 8-layer PCB which consists of the Slice-board circuit, keeping Radio frequency characteristics and a slot type connector.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.7A
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• pp.485-492
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• 2003

This paper proposes a transmission probability control scheme for guaranteeing fair packet transmissions in CDMA slotted ALOHA system. In CDMA slotted ALOHA system, the packets transmitted in the same slot act as multiple access interference, so that unsuccessful packet transmissions are caused entirely by multiple access interference. Therefore, in order to maximize the system throughput, the number of simultaneously transmitted packets should be kept at a proper level. In the proposed scheme, the base station calculates the packet transmission probability of mobile stations in the next slot according to the offered load and then broadcasts this probability to all the mobile stations. Mobile stations, which have a packet to transmit, attempt to transmit packet with the received probability. Simulation results show that the proposed scheme can offer better system throughput and average delay than the conventional scheme, and guarantee a good fairness among all mobile stations regardless of the offered load.

• The Journal of the Korea institute of electronic communication sciences
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• v.1 no.1
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• pp.70-80
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• 2006

The large portion of communication service areas move from a legacy wire-line voice service to mobile data service. For the purpose of satisfaction on market need, many communication systems should be installed and upgraded based on a mobile wide-band transmission facility. Recently, large part of communication service is based on internet protocol by packet switch techniques and required new technologies such as multimedia processing, QoS achievement, and mobility managememobile communication network such as IS-95A/B and CDMA2000-1X. In this paper, I analyzed the network architecture and service provision methods. in CDMA2000-1X nt. In korea, a CDMA communication technique is standardized for digital mobile communication systems. By using the analysed results, I will extract an efficient method for network evolution and a core technique for next generation mobile communication network.

• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.97-100
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• 2001

The performance of mobile radio communication system is dependent on various factors such as channel environment. Especially, the number of multipath components of mobile radio channel and multipath delay property in CDMA system for different bandwidths are changed. Therefore, using multipath components, Rake receiver provides improvement of performance of W-CDMA system is evaluated by computer simulation over the types of ITU-R wideband channel model and spreading rate. The result shows that the performance of CDMA adapting RAKE receiver is Improved by the increase of multipath components in equal level of the received power.